Petroleum diesel combustion is a major source of greenhouse gas (GHG). It is also a major source of other air contaminants including NOx, SOx, CO and volatile organic compounds. Algae have emerged as one of the most promising sources for biodiesel production. In this study, a higher algae growth rate was observed in the experiments with excess Na 2 SiO 4 , trace metals, Na 2 EDTA and excess vitamin solution, the increase was above 300%. It was also observed that the experiment that was supplied with CO 2 (without simultaneous sunlight exposure) for one hour, for 25 days and the beaker with excess NaH 2 PO 4 solution, have shown a slower growth rate than the control. The results of the experiment on the effect of sunlight exposure for certain times daily for 25 days show that the growth rate is directly proportional to increase of sunlight exposure time (during the 90 min). The results of the experiment on the effect of simultaneous exposure to sunlight and CO 2 for certain times daily, for 25 days, show that the growth rate is directly proportional to the increase of sunlight and CO 2 exposure time.

The current situation in many developing countries is that, vegetable oils are replacing animal fats because of health concerns and cost. The objective of the study was to compare the iodine value, acid value, ester value, peroxide value, saponification number and cholesterol content of some locally produced vegetable oils like refined marula cooking oil, marula traditional cooking oil, marula cosmetic oil, melon oil, ximenia oil viz. olive oil and commercial sunflower oil. The physicochemical analysis helps to justify the usage of these different traditional oils. The analysis showed that marula cooking oil is close to olive oil in the unsaturation level and better than olive oil in ester value, peroxide value and has lower cholesterol content.